In a conventional electrophotographic printer (not shown), a photosensitive device such as a drum or the like (hereinafter "drum") is uniformly electrostatically charged, a light device such as an LED array or a laser selectively emits light onto the drum to form an electrostatic latent image thereon, toner is applied to the electrostatic latent image on the drum to develop the image into a toner image, a transfer charger transfers the toner image from the drum to a printing sheet, and a pair of heat rollers or the like fixes the transferred toner on the printing sheet.
The toner in the printer is typically supplied from either a non-removable developer hopper, or more commonly from a removable self-contained toner cartridge. It is known in the prior art to include within such developer hopper or toner cartridge a rotating toner stirrer to prevent the toner from clumping inside the developer hopper or toner cartridge, and also to ensure that a steady supply of toner is provided from such developer hopper or toner cartridge. It is also known in the prior art to form the main part of the stirrer from stainless steel or the like (hereinafter "stainless steel") in the shape of a straight rod or one or more helical members, among other things. However, such a stainless steel stirrer is relatively expensive in terms of material costs and manufacturing costs.
Oftentimes it is less expensive in terms of material costs and manufacturing costs to construct an object from a polymer rather than from stainless steel. However, such a polymer normally has less rigorous mechanical, tensile, and other properties than stainless steel, with the result that a polymer version of a part cannot perform the same functions as an otherwise identical stainless steel version of the part. As should be evident, then, it is not practical to replace a stainless steel stirrer in an electrophotographic printer with an otherwise identical polymer stirrer. Accordingly, a need exists for an improved stirrer for such printer, where such stirrer can be constructed from an appropriate relatively less expensive polymer, and where such stirrer is less expensive to manufacture. Moreover, a need exists for such stirrer that is as reliable and sturdy as prior art stainless steel stirrers.